1. Field of the Invention
The present invention relates to low-voltage type connectors having a high direct current capacity for use with battery-powered heavy duty appliances.
The present invention further relates to a system for operating battery powered, hand-held power tools and appliances, including tools and appliances having a high direct current capacity.
2. Description of Background
In recent years, low-voltage direct current (e.g., 12 VDC) hand-held appliances and tools have proliferated for use in the car and around the home. Some appliances, such as the hand-held automobile vacuum cleaners and automobile polishers, are intended for operation using power supplied from the car battery. These appliances, which are relatively low current devices (i.e., 2-6 amps), typically employ a plug connector compatible with the socket component of a conventional, dash-mounted automotive cigarette lighter. The necessity for use of these appliances in close proximity to a vehicle having a lighter socket has restricted somewhat the utilization of the same appliances around the home.
Many hand-held tools used around the home, in comparison, require relatively high current levels (i.e., 8-20 amps). These high current appliances include hedge trimmers, grass trimmers, etc., which can seriously tax the capacity of self-contained battery packs which typically are of the NiCd variety. A portable, lead-acid battery pack has been proposed as offering increased power capacity and longer operation times between charging. As the proposed battery pack would not be self-contained with the power tool or appliance itself, an important feature of the proposed system would be a low-voltage high current capacity connector assembly that would enable the battery pack to be connected and disconnected to a variety of different tools.
Moreover, because of the existence of a variety of automotive appliances having cigarette lighter socket-compatible low current plug connectors, a high current capacity connector assembly that could, without modification, accommodate existing low-voltage, low current plug connectors would extend the usefulness of the proposed system.
An operating system using a portable battery pack having increased power capacity and longer operation times between charging would be highly desirable for these high direct current tools. The system should enable the battery pack to be selectively connectable to a variety of different tools to maximize utility. Moreover, an ability to accommodate existing low current plug connectors would further extend the usefulness of the system.
Another feature desireable in such portable power supply systems relates to the ability to connect devices which have different voltage requirements. For example, while many of the high current devices described above may utilize 12 volts as the operating voltage, other hand-held tools operate at 24 volts; such tools typically have lower current requirements than those operable at 12 volts. It is therefore desireable to provide a portable supply permitting connection of both types of tools so that either can be powered from the same source.
A further feature associated with such portable supplies relates to recharging the batteries of the supply system. In conventional prior art systems, recharging is typically accomplished via a plug or other connector assembly whose function is dedicated strictly to recharging. In order to minimize the number of components, and hence cost and complexity of such systems, it is desireable to provide a charging arrangement utilizing the same connector assemblies otherwise used for powering the various tools that can be connected to the supply.